The Harvard Catalyst (HC) TL1 Training Program provides the organizational, curricular, and intellectual infrastructure for creating and mentoring a community of students and faculty engaged in disease-oriented research and the translation of principles of human biology to clinical medicine. TL1 offers an interdisciplinary PhD program that integrates human biology and translational medicine training for graduate students in life sciences graduate programs across Harvard University (HU). For the past nine years, the TL1 Program has provided a cornerstone of support for some of the best graduate students in the Leder Human Biology Program (LHB Program). TL1 currently supports 39 students, integrated in the larger community of 78 students in the LHB program. Students in the TL1 program come from graduate programs across Harvard University, including Biological and Biomedical Sciences, Neurosciences, Immunology, Systems Biology, and Chemistry and Chemical Biology. The two TL1 Co-Leads, Connie Cepko, PhD, and Thomas Michel, MD, PhD, have extensive and complementary expertise in basic, translational, and clinical science, and longstanding experience in the leadership of graduate training programs. Going forward, TL1 will continue to represent a key component of the HC Translational Workforce Development (see Core D. Translational Endeavors). TL1 will expand to incorporate new training programs in team science, quantitative methods, and bioinformatics that complement current programs to prepare an effective biomedical research workforce of the future. Each year TL1 will select seven new first-year graduate students. The average time to obtaining the PhD degree for TL1 students is 5.7 years. Awardees will be supported for the first two years of their PhD studies, after which support will come from their PhD mentors' research program, or from institutional funds or foundations. The objectives of the TL1 Training Core are to: (Aim 1) Provide a graduate curriculum with a focus on quantitative team-based active learning methods that will train graduate students in the mechanisms and methodologies of human biology and disease-oriented T0/T1 discovery, and provide them with direct clinical contact with patients and physicians; (Aim 2) Establish a context for human disease-oriented translational research in paracurricular activities across HC that connect clinical medicine with student research in human biology and translational medicine; and (Aim 3) Nurture a diverse community of students and faculty with shared goals of applying rigorous methodologies to the translation of basic discoveries to prevention, diagnosis, and treatment of human disease, while also reaching out into the broader Boston community. TL1 will select and support the training of the best graduate students committed to careers in human biology and translational medicine, and who will benefit from and contribute to the discipline at HU and beyond.